Container throughput in China's 10 largest ports jumped 21.9 percent on the year to 12.4 million TEUs in May this year, according to estimates by industry researcher AXS-Alphaliner.

The strong performance, which marks the highest-ever monthly volumes registered, was pushed by a 33 percent-increase of Chinese exports and a 57 percent-rise of imports.

Six of the top ten ports posted record volumes, led by Ningbo, where these surged 52 percent on the year to 1.2 million TEUs. The other ports were Shanghai, Guangzhou, Tianjin, Xiamen and Dalian.